bio exam section 5 ecology

  1. 1869 Ernst Haeckel
    coins term “ecology” defining this branch of the biological sciences
  2. 2000 Earth’s human population
    at 6 billion with an expected doubling time of less than 25 years.
  3. Ecology
    • the branch of biology concerned with the relationships between organisms and their environment. Ecology examines the manner in which organisms affect their environment, and are in turn affected by their environment.
    • Ecologists may study nature at various levels of organization including species, populations, communities, ecosystems, biomes, and the biosphere.
  4. Species -
    a group of similar organisms that freely interbreed to produce fertile offspring
  5. Populations -
    an interbreeding group of individuals of a particular species isolated from other groups
  6. Community -
    all populations in a certain geographical area
  7. Ecosystem -
    • the living (biotic) and nonliving (abiotic) components interacting within a community.
    • The biotic factors would include the various organisms present in the community; while the abiotic factors would include such variables as sunlight, air, water, nutrients, oxygen, wind, pH, and fire.
  8. Biome -
    • large biogeographical regions of the earth characterized by a certain climate and populated by characteristic assemblages of plants and animals. Some of the earth's major biomes include the
    • tropical rain forest
    • temperate deciduous forest
    • northern coniferous forest (taiga)
    • savanna
    • temperate grassland (prairie)
    • tundra
    • desert
  9. Biosphere -
    the narrow band around the earth within which life exists
  10. density -
    number of individuals per unit area
  11. dispersion -
    the way individuals are spaced within their area
  12. dispersion patterns
    • clumped
    • uniform
    • random
  13. clumped
    clumped: most frequent pattern; Individuals are clustered together in groups in response to uneven distribution of resources, tendency of offspring to remain with parents, or some type of social order
  14. uniform
    uniform: in which members of the population maintain a minimum distance from one another, generally indicates strong intraspecific competition
  15. random
    random: least common pattern; usually occurs because members of a species do not frequently interact with one another or are not heavily influenced by the microenvironments within their habitat
  16. growth rate
    • rate of natural increase (r)
    • depends on
    • Number born each year
    • Number of individuals who die each year
  17. biotic potential
    • highest possible rate of population growth
    • maximum inherent capacity for an organism to reproduce
    • “r-selected species”
  18. carrying capacity (K)
    • the number of members of a population that an area can maintain with no increase or decrease
    • “K-selected species”
  19. r selection
    • Small
    • Short Life Span
    • Mature Fast
    • Many Offspring -no parental care
    • Tend to be good dispersers and colonizers
    • Rely on rapid dispersal to new unoccupied environments
  20. k selection
    • large size
    • long life span
    • slow to mature
    • produce few offspring
    • expend much energy in care of offspring
    • Tend to be strong competitors; Often specialists
    • Rely on competitive superiority to get limited resources
  21. limitations of population growth
    • density dependent (biotic) factors: disease, starvation, predation
    • density-independent (abiotic) factors: climate, natural disaster
  22. survivorship curves
    • exponential growth: J shaped curve; 2 phases. lag phase (slow growth) and exponential growth phase (growth is accelerating)
    • logistic growth: S shaped or logistic growth curve (growth slows down)
    • deceleration phase: rate of population growth slows down; Stable equilibrium phase (little if any growth)
  23. 3 major age groups of population
    • pre-reproductive
    • reproductive
    • post-reproductive
  24. when the pre-reproductive group is largest
    • birthrate is higher than death rate
    • increasing population
    • diagram is pyramid shaped
  25. when the pre-reproductive and the reproductive group are equal
    • bell shaped diagram
    • stable population
    • post reproductive group still smallest (because of mortality)
  26. the pre-reproductive group is smaller than the reproductive group
    • urn shaped diagram
    • decreasing population
    • post-reproductive group is now largest
  27. Biological Community (characteristics)
    • diversity: variety of different types of organisms found within the community
    • prevalent vegetation: dominant plants 
    • stability: ability to resist change and to return to its original species composition after being disturbed 
    • trophic structure: the feeding relationships among the various species making up the community 
  28. mutualism      (+ +)
    • –Both members of the association benefit
    • abundance of both species increases
  29. commensalism   (+ 0)
    • –One species benefits and the other is neither benefited nor harmed
    • abundance of one species increases and the other is not affected
  30. parasitism     (+ -)
    • –Parasite derives nourishment from a host, and may use host as habitat and mode of transmission
    • abundance of parasite increases, and abundance of host decreases
  31. interspecific competition
    • members of different species try to use the same limited resource
    • Eventually, one species would be displaced
  32. intraspecific competition
    Individuals of the same species have very similar resource requirements and if these resources are limiting, they will compete for access.
  33. niche -
    an organism's functional role within an ecosystem
  34. competitive exclusion principle -
    only one organism can occupy a particular niche
  35. predator-prey relationships
    • Predator: feeds on another organism
    • is larger
    • has lower reproductive rate
    • Prey: usually entirely consumed
    • has a higher reproductive rate
    • is smaller
    • Predation increases diversity by reducing competition
  36. Batesian mimicry
    • mimic is harmless
    • Viceroys (harmless) and Monarchs (dangerous)
  37. Mullerian mimicry
    • both mimic and model are harmful
    • bumble bee & yellow jacket (both harmful)
  38. Ecological succession –
    • transition of the species composition of an ecosystem after a disturbance
    • (change following a disturbance)
  39. primary succession
    • starts with no soil.
    • Bare rock, lava flow
    • Lichens (some kind of fungus with autotrophic partner)
    • Mosses
    • Grasses
    • Sedges
  40. secondary succession
    • starts with soil  present.
    • colonization by pioneer species
    • ex. harvested corn field that eventually becomes a mixture of shrubs and trees
  41. producers (autotrophs)
    Algae, cyanobacteria, plants
  42. consumers (heterotrophs) primary, secondary, and tertiary consumers
    • Primary consumers: Herbivores; they eat plants
    • secondary consumers: carnivores; meat
    • tertiary consumers: omnivores
  43. pyramids of energy, biomass, numbers
    • pyramids: Only about 10% of the energy of one trophic level is available to the next trophic level (explains why few top carnivores can be supported in a food web)
    • may be based on the number of organisms or the amount of biomass at each trophic level
  44. chemical cycling
    the pathway by which chemicals circulate through ecosystems
  45. chemical cycling may involve
    • reservoir: Source normally unavailable to producers (fossil fuels, minerals, sediments)
    • exchange pool: Source from which organisms generally take chemicals (atmosphere, soil, water)
    • biotic community: Chemicals remain in food chains, perhaps never entering a pool
  46. water (hydrological) cycle
    • evaporation and transpiration
    • evaporation over the ocean is not compensated for by precipitation. precipitation over land results in bodies of fresh water plus groundwater, including aquifers. Eventually all water returns to the oceans
  47. carbon cycle -
    • photosynthesis, cellular respiration, and combustion
    • carbon dioxide in the atmosphere is an exchange pool; both terrestrial and aquatic plants and animals exchange carbon dioxide with the atmosphere.
    • living and dead organisms serve as reservoirs for the carbon cycle because they contain organic carbon.
    • human activities increase CO2 and other greenhouse gases contributing to global warming and climate change
  48. nitrogen cycle -
    • "nitrogen-fixing bacteria"
    • plants cannot use nitrogen gas from the atmosphere. during nitrogen fixation, N2 converts to ammonium, making nitrogen available to plants.
    • nitrification is the production of nitrates while denitrification is the conversion of nitrate back to N2 which enters the atmosphere.
    • human activities increase transfer rates in the nitrogen cycle. acid deposition occurs when nitrogen oxides enter the atmosphere, combine with water vapor, and return to earth in precipitation (acid rain)
  49. phosphorus cycle
    • no atmospheric phase
    • weathering of rocks
    • geological upheavals move phosphorous from the ocean to land.
    • slow weathering of rocks returns phosphorus to the soil
    • most phosphorus is recycled within a community and phosphorous is a limiting nutrient  
  50. biomes
    the world's major biomes [the tropical rainforest, temperate deciduous forest, northern coniferous forest (taiga),savanna, temperate grassland (prairie), tundra, and desert] may be compared based on geographical location, climate, soil quality, annual rainfall, characteristic plants and animals; as well as, the environmental problems currently facing each biome. 
  51. forested biomes
    • 1. tropical rain forest
    • 2. temperate deciduous forest
    • 3. northern coniferous forest (taiga)
  52. grasslands
    • 4. savanna
    • 5. temperate grassland (prairie)
  53. treeless biomes
    • 6. tundra
    • 7. desert
  54. tropical rain forest
    geographical location
    soil quality
    characteristic or unique species
    environmental problems
    • near the equator; covering 7% of earth surface
    • always warm weather and plentiful rainfall
    • nutrient poor soil
    • 50% of species found on earth are in the tropical rainforest
    • deforestation without allowing time for forest to re-grow
  55. temperate deciduous forest
    soil quality
    characteristic or unique species
    environmental problems
    • south of the taiga in eastern north America, eastern Asia, and much of Europe
    • moderate with high rainfall; well-defined seasons (trees lose leaves in fall)
    • rich soil
    • small herbivores (squirrels etc.) ground birds like turkey, amphibians and reptiles
    • ?
  56. northern coniferous forest (taiga)
    soil quality
    characteristic or unique species
    environmental problems
    • Northern Europe, Asia, and North America; 11% of earth's landmasses
    • cold; high latitude
    • normal?
    • moose, cone-bearing trees, birds, beavers, wolves/mountain lions/bears
    • ?
  57. savanna
    soil quality
    characteristic or unique species
    environmental problems
    • central and southern africa
    • relatively cool dry season followed by hot rainy season
    • large expanses of grasses with relatively few trees
    • ? probably not very rich
    • trees that can survive drought, large herbivores (zebras, elephants etc.) large population of carnivores (lions, cheetahs, etc.)
    • ?
  58. temperate grasslands (prairie)
    soil quality
    characteristic or unique species
    environmental problems
    • Russian steppes, south American pampas, north American prairies
    • winters bitterly cold, summers hot and dry; tall grass prairie receives more rainfall than short grass prairie
    • used to have large mammals like bison; now small mammals like mice, prairie dogs, rabbits. predators are hawks, snakes, coyotes
    • the grasslands are being converted into agricultural lands
  59. tundra
    soil quality
    characteristic or unique species
    environmental problems
    • nearest the polar regions; covers 20% of earth's land surface
    • cold much of the year; long harsh winters, short summers; very little rainfall
    • nutrient poor soil because of frozen topsoil
    • few animals in the winter, ox, arctic foxes, snowy owls; more animals in the summer migrate there
    • ?
  60. desert
    soil quality
    characteristic or unique species
    environmental problems
    • both in northern and southern hemispheres; 30% of earth's land surface
    • very little rainfall, days are hot, nights are cold
    • ?
    • plants adapted to little rainfall,
    • reptiles, insects, rodents; larger mammals like kit fox prey on rodents as do hawks
Card Set
bio exam section 5 ecology
study guide for section 5 ecology & the growth of the environmental science movement